The present invention relates to a new and improved construction of apparatus for regulating the lapping pressure during the lapping of two bevel gears at a lapping machine, said apparatus being of the type incorporating a device for driving the one bevel gear and for braking the other bevel gear and further including a control mechanism for adjusting the desired lapping pressure.
With a state-of-the-art apparatus of this general type there are provided two direct-current motors for the respective drive of the one bevel gear and for braking the other bevel gear. With the aid of a control mechanism or device there are compared with one another the drive moment of the one motor and the braking moment of the other motor by means of the current of the direct-current motors and such drive moment and braking moment adjusted to a desired reference value.
It has however been found that the lapping pressure, i.e. the force with which the teeth flanks which slide upon one another are pressed against one another, is not solely dependent upon the rotational moment. In the case of special transmissions or gearings with extreme displacement of the axle it is however important to be able to determine the lapping pressure itself and not only the aforementioned rotational moment. The prior art method thus has the drawback that the lapping pressure cannot be measured, only the rotational moment.
Thus, if there occurs, on the one hand, considerable deviations between the measured rotational moment and the actual lapping pressure and, if, on the other hand, it is necessary that certain bevel gears are only lapped with a slight lapping pressure, then the aforementioned apparatus is completely incapable of properly performing, especially if there are also to be taken into account disturbance magnitudes which are dependent upon the temperature and rotational speed.